– Black holes swallow matter, but they also squirt out really energetic jets of material. Now we’ve seen evidence that they can do both at the same time, says Anthony Rushton, astronomer at Onsala Space Observatory and ESO, who led the study.

Rushton and his team monitored radio waves from Cygnus X-1 with a global network of radio telescopes. At the same time they followed its brightness in X-rays with the NASA satellite RXTE (Rossi X-ray Timing Explorer).

- Our X-ray measurements tell us about how much matter is falling into the black hole. At the same time we took high-precision images of the jet in radio waves to see how it changed, says Anthony Rushton.

Rushton and his team got a surprise. Even when the X-rays showed that the black hole was having a good meal, the radio images showed that its jet was still active, throwing out particles into space.

- This is telling us that jets are fundamental pieces in the puzzle of how matter falls into a black hole, Rushton concludes.

Contacts: Robert Cumming, Onsala Space Observatory, tel +46 70 49 33 114, robert.cumming@chalmers.se, or Anthony Rushton, Onsala Space Observatory, tel +46 31 772 55 29, anthony.rushton@chalmers.se

The research paper, "A weak compact jet in a soft state of Cygnus X-1" is scheduled for publication in the journal Monthly Notices of the Royal Astronomical Society. The paper is also available at http://arxiv.org/abs/1110.4374. The team is A. Rushton (Onsala Space Observatory and ESO), J.C.A. Miller-Jones (Curtin University of Technology, Australia), R. Campana (INAF/IASF-Roma, Italy), Y. Evangelista (INAF/IASF-Roma, Italy), Z. Paragi (JIVE, Netherlands and MTA Research Group for Physical Geodesy and Geodynamics, Budapest, Hungary), T.J. Maccarone (University of Southampton, UK), G.G. Pooley (Cavendish Laboratory, Cambridge, UK), V. Tudose (ASTRON, Netherlands, and Astronomical Institute of the Romanian Academy, Romania), R.P. Fender (University of Southampton, UK), R.E. Spencer (Jodrell Bank Centre for Astrophysics, University of Manchester, UK) and V. Dhawan (NRAO, USA).